Some are good but others, don't get me started! OK, the worst ones use Wiki to provide substitute content for their miserable lives. They spend hours a day, day in day out weeks on end, merging into months and years, and they simply get off by trolling and targeting contributors. Contributors are those that actually write for Wikipedia and they are often highly educated and knowledgeable experts who actually conduct researched the topics they write about and also for nothing but grief the RCPs dish out, they offered it all up to the world free on Wikipedia.
RCP editors are techno-sadists Contributors must be their willing masochistic victims.
It means to read before posting/typing. It's often used on forums or chatrooms when people try to point out something already discussed.
B: It's the people's dictionary of slangs.
Later on person C will read A's question and answer (Before reading the rest!):
C: It's a dictionary!!(!)
B: It was already answered, RCP please.